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Superior Central Nucleus
The median raphe nucleus (MRN), also known as the superior central nucleus, is a nucleus in the brainstem composed of polygonal, fusiform, and piriform neurons, which exists rostral to the pontine raphe nucleus. The median raphe nucleus is one of several raphe nuclei that lies on the brainstem midline. It is one of two nuclei that are situated more superior to the others. The second of these nuclei is the dorsal raphe nucleus (DRN). The MRN extends from the lower part of the dorsal raphe nucleus to an approximate position at the decussation of the superior cerebellar peduncle . The MRN projects extensively to the hippocampus, which is known to be essential for the formation of long-term memory. One study found that this raphe–hippocampus pathway plays a critical role in regulating hippocampal activity and likely associated memory consolidation processes. It has also been found to play a role in anxiety and depression, as one of the few parts of the brain that creates tryptopha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raphe Nuclei
The raphe nuclei (, "seam") are a moderate-size cluster of nuclei found in the brain stem. They have 5-HT1 receptors which are coupled with Gi/Go-protein-inhibiting adenyl cyclase. They function as autoreceptors in the brain and decrease the release of serotonin. The anxiolytic drug Buspirone acts as partial agonist against these receptors. Selective serotonin reuptake inhibitor (SSRI) antidepressants are believed to act in these nuclei, as well as at their targets. Anatomy The raphe nuclei are traditionally considered to be the medial portion of the reticular formation, and appear as a ridge of cells in the center and most medial portion of the brain stem. In order from caudal to rostral, the raphe nuclei are known as the '' nucleus raphe obscurus'', the '' nucleus raphe pallidus'', the '' nucleus raphe magnus'', the '' nucleus raphe pontis'', the '' median raphe nucleus'', ''dorsal raphe nucleus'', ''caudal linear nucleus''. In the first systematic examination of the raph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Posterior Cortex
Posterior cortex usually means the posterior (back) part of the complete cerebral cortex and includes the occipital, parietal, and temporal cortices. In other words, the posterior cortex includes all the cerebral cortex without the frontal cortex. In combination with specific cortical areas, 'posterior cortex' usually refers to the posterior (back) part of that cortical area. For example: the posterior parietal cortex is the posterior part of the parietal cortex and the posterior cingulate cortex is the posterior part of the cingulate cortex. Function of the posterior cortex The posterior cortex is the “sensory” cortex, much as the frontal cortex is the “action” cortex. The posterior cortex is responsible for encoding the sensory content (visual, auditory, and tactile) of any experience (both real and imaginary experience). The posterior cortex with the exception of the primary sensory areas ( Primary visual cortex (V1), primary auditory cortex, and somatosensory cort ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long-term Potentiation
In neuroscience, long-term potentiation (LTP) is a persistent strengthening of synapses based on recent patterns of activity. These are patterns of synaptic activity that produce a long-lasting increase in signal transmission between two neurons. The opposite of LTP is long-term depression, which produces a long-lasting decrease in synaptic strength. It is one of several phenomena underlying synaptic plasticity, the ability of chemical synapses to change their strength. As memories are thought to be encoded by modification of synaptic strength, LTP is widely considered one of the major cellular mechanisms that underlies learning and memory. LTP was discovered in the rabbit hippocampus by Terje Lømo in 1966 and has remained a popular subject of research since. Many modern LTP studies seek to better understand its basic biology, while others aim to draw a causal link between LTP and behavioral learning. Still, others try to develop methods, pharmacologic or otherwise, of enhanci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hallucinogens
Hallucinogens, also known as psychedelics, entheogens, or historically as psychotomimetics, are a large and diverse class of psychoactive drugs that can produce altered states of consciousness characterized by major alterations in thought, mood, and perception as well as other changes. Hallucinogens are often categorized as either being psychedelics, dissociatives, or deliriants, but not all hallucinogens fall into these three classes. Examples of hallucinogens include psychedelics or serotonin 5-HT2A receptor agonists like LSD, psilocybin, mescaline, and dimethyltryptamine, DMT; dissociatives or NMDA receptor antagonists like ketamine, phencyclidine, PCP, dextromethorphan, DXM, and nitrous oxide; deliriants or antimuscarinics like scopolamine and diphenhydramine; cannabinoids or endocannabinoid system, cannabinoid CB1 receptor, CB1 receptor agonists like tetrahydrocannabinol, THC, nabilone, and JWH-018; kappa-opioid receptor, κ-opioid receptor agonists like salvinorin A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serotonin Receptor Agonist
A serotonin receptor agonist is an agonist of one or more serotonin receptors. They activate serotonin receptors in a manner similar to that of serotonin (5-hydroxytryptamine; 5-HT), a neurotransmitter and hormone and the endogenous ligand of the serotonin receptors. Non-selective agonists Serotonergic psychedelics such as tryptamines (e.g., psilocybin, psilocin, , 5-MeO-DMT, bufotenin), lysergamides (e.g., , ergine ()), phenethylamines (e.g., mescaline, 2C-B, 25I-NBOMe), and amphetamines (e.g., , ) are non-selective agonists of serotonin receptors. Their hallucinogenic effects are specifically mediated by activation of the 5-HT2A receptor. Drugs that increase extracellular serotonin levels such as serotonin reuptake inhibitors (e.g., fluoxetine, venlafaxine), serotonin releasing agents (e.g., fenfluramine, ), and monoamine oxidase inhibitors (e.g., phenelzine, moclobemide) are indirect non-selective serotonin receptor agonists. They are used variously as antidepressant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Psilocin
Psilocin, also known as 4-hydroxy-''N'',''N''-dimethyltryptamine (4-HO-DMT), is a substituted tryptamine alkaloid and a serotonergic psychedelic. It is present in most psychedelic mushrooms together with its phosphorylated counterpart psilocybin. Psilocybin, as well as synthetic esters such as 4-AcO-DMT (psilacetin; ''O''-acetylpsilocin) and 4-PrO-DMT (''O''-propionylpsilocin), are prodrugs of psilocin. Acting on the serotonin 5-HT2A receptors, psilocin's psychedelic effects are directly correlated with the drug's occupancy at these receptor sites. It also interacts with other serotonin receptors and targets. The subjective mind-altering effects of psilocin are highly variable in their qualitative nature but resemble those of lysergic acid diethylamide (LSD) and ''N'',''N''-dimethyltryptamine (DMT). Psilocin is a Schedule I drug under the Convention on Psychotropic Substances. Uses Psilocin is used recreationally, spirituality or shamanically, and medically. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lysergic Acid Diethylamide
Lysergic acid diethylamide, commonly known as LSD (from German ; often referred to as acid or lucy), is a Semisynthesis, semisynthetic, Hallucinogen, hallucinogenic compound derived from ergot, known for its powerful psychological effects and Serotonin, serotonergic activity. It was historically significant in psychiatry and 1960s counterculture; it is currently legally restricted but experiencing renewed scientific interest and increasing use. When taken orally, LSD has an onset of action within 0.4 to 1.0 hours (range: 0.1–1.8 hours) and a duration of effect lasting 7 to 12 hours (range: 4–22 hours). It is commonly administered via tabs of Blotting paper, blotter paper. LSD is extremely potent, with noticeable effects at doses as low as 20 Microgram, micrograms and is sometimes taken in much smaller amounts for microdosing. Yet no fatal human overdoses have been documented. LSD is mainly used recreationally or for spiritual purposes. LSD can cause mystical experiences. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TPH2
Tryptophan hydroxylase 2 (TPH2) is an isozyme of tryptophan hydroxylase found in vertebrates. In humans, TPH2 is primarily expressed in the serotonergic neurons of the brain, with the highest expression in the raphe nucleus of the midbrain. Until the discovery of TPH2 in 2003, serotonin levels in the central nervous system were believed to be regulated by serotonin synthesis in peripheral tissues, in which tryptophan hydroxylase is the dominant form. Function Tryptophan hydroxylase (TPH; EC 1.14.16.4) is the rate-limiting enzyme in the synthesis of serotonin (5-hydroxytryptamine, or 5HT). 5HT is causally involved in numerous central nervous activities, and it has several functions in peripheral tissues, including the maintenance of vascular tone and gut motility. upplied by OMIMref name="entrez"> Disabling this enzyme with drugs (especially p-chlorophenylalanine aka PCPA or Fenclonine) has allowed researchers to investigate the effects of very low serotonin levels on humans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fenclonine
Fenclonine, also known as ''para''-chlorophenylalanine (PCPA), acts as a selective and irreversible inhibitor of tryptophan hydroxylase, which is a rate-limiting enzyme in the biosynthesis of serotonin. It has been used experimentally to treat carcinoid syndrome, but the side effects, mostly hypersensitivity reactions and psychiatric disturbances, have prevented development for this use. The effects of serotonin depletion from fenclonine are so drastic that serotonin cannot even be detected immunohistochemically within the first day after administration of a control dose. Tryptophan hydroxylase activity can be detected neither in cell bodies or nerve terminals. After one week 10% of control values (the baseline extrapolated for the study) had replenished in the raphe nucleus The raphe nuclei (, "seam") are a moderate-size cluster of nuclei found in the brain stem. They have 5-HT1 receptors which are coupled with Gi/Go-protein-inhibiting adenyl cyclase. They function as aut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dentate Gyrus
The dentate gyrus (DG) is one of the subfields of the hippocampus, in the hippocampal formation. The hippocampal formation is located in the temporal lobe of the brain, and includes the hippocampus (including CA1 to CA4) subfields, and other subfields including the dentate gyrus, subiculum, and presubiculum. The dentate gyrus is part of the trisynaptic circuit, a neural circuit of the hippocampus, thought to contribute to the formation of new episodic memories, the spontaneous exploration of novel environments and other functions. The dentate gyrus has toothlike projections from which it is named. The subgranular zone of the dentate gyrus is one of only two major sites of adult neurogenesis in the brain, and is found in many mammals. The other main site is the subventricular zone in the ventricular system. Other sites may include the striatum and the cerebellum. However, whether significant neurogenesis takes place in the adult human dentate gyrus has been a matter of d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serotonin
Serotonin (), also known as 5-hydroxytryptamine (5-HT), is a monoamine neurotransmitter with a wide range of functions in both the central nervous system (CNS) and also peripheral tissues. It is involved in mood, cognition, reward, learning, memory, and physiological processes such as vomiting and vasoconstriction. In the CNS, serotonin regulates mood, appetite, and sleep. Most of the body's serotonin—about 90%—is synthesized in the gastrointestinal tract by enterochromaffin cells, where it regulates intestinal movements. It is also produced in smaller amounts in the brainstem's raphe nuclei, the skin's Merkel cells, pulmonary neuroendocrine cells, and taste receptor cells of the tongue. Once secreted, serotonin is taken up by platelets in the blood, which release it during clotting to promote vasoconstriction and platelet aggregation. Around 8% of the body's serotonin is stored in platelets, and 1–2% is found in the CNS. Serotonin acts as both a vasoconstrictor and vas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brainstem
The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is continuous with the thalamus of the diencephalon through the tentorial notch, and sometimes the diencephalon is included in the brainstem. The brainstem is very small, making up around only 2.6 percent of the brain's total weight. It has the critical roles of regulating heart and respiratory system, respiratory function, helping to control heart rate and breathing rate. It also provides the main motor and sensory nerve supply to the face and neck via the cranial nerves. Ten pairs of cranial nerves come from the brainstem. Other roles include the regulation of the central nervous system and the body's sleep cycle. It is also of prime importance in the conveyance of motor and sensory pathways from the rest of the brain to the body, and from the b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
